1. Field of the Invention
This invention relates to an ink jet recording method, and in particular to an ink jet recording method in which the fixativeness after printing is effected on a recording sheet such as a sheet material is improved.
2. Related Background Art
An apparatus for printing characters (including ordinary images such as figures) by the use of an ink jet head, such as an ink jet printer or an ink jet recorder, is designed such that ink droplet discharge means provided in the ink jet head is driven on the basis of character information and character patterns are recorded by print dots formed by ink droplets adhering to a recording sheet.
In such an ink jet recording method, character dots are formed by liquid ink droplets and therefore, the fixativeness after printing poses a problem.
That is, if the fixativeness is poor, there occur various inconveniences such that, for example, undried characters are absorbed onto a second sheet material, printed characters are smeared when a second sheet material is fed after printing, and a printed sheet material becomes smeared when being handled by fingers.
So, as a method of improving the fixativeness of printed characters, use has heretofore been made of a method of heating a recording sheet after printing and expediting the desiccation thereof, or increasing the amount of sheet feed until the sheet is discharged after printing, or decreasing the pulse width of an ink discharge driving voltage.
Incidentally, recently the number of dots per character is increasing to improve the quality of print or improve the resolution of image, and for example, there is seen the tendency toward an increase from a head of 9 vertical dots to 24 dots, and further to 32 dots or 48 dots.
Such an increased number of character dots makes it difficult to improve the fixativeness only by the conventional method of expediting desiccation as described above. And particularly in the case of solid color image printing, block character printing, hollow character printing or printing of a pattern having many prints of high dot density such as a bit image, there has been the problem that the fixativeness is poor and the quality of print cannot be maintained.
Also, the fixativeness of printed characters is governed by environmental conditions such as temperature and humidity, but the prior art has encountered difficulties in coping with these environmental conditions